Device and method for controlling the beginning of a tool operation in fish treatment machine

ABSTRACT

In a device and method for controlling the commencement of operation of at least one tool in a fish processing machine, a guide element penetrates the interior of the fish so as to perform alignment of the fish before the tool begins its application. A monitoring device associated with the guide element includes a sensor for determining the guide element/fish position. An evaluating unit connected to the sensor compares nominal and actual position values. On reaching an adjustable nominal position value, a signal for actuating the tool is triggered. Therefore, the tool comes into operation only when the monitoring device yields an actual value for the fish position which corresponds to the nominal value when the guide element has penetrated properly.

FIELD OF THE INVENTION

[0001] The invention concerns a device and a method for controlling thecommencement of operation of at least one tool in a fish processingmachine in which tool and fish are moved relative to each other along agiven conveying path, wherein the position of the fish in relation tothe tool is determined by means of a guide element which penetrates intothe interior of the fish, and after alignment of the fish as a result ofpenetration of this guide element the tool begins its application to orintervention in the fish.

STATE OF THE ART

[0002] In the processing or treatment of fish it is necessary in manycases, particularly when the fish is not yet gutted, that is, theabdominal cavity is not yet cleaned, to align it in the region thereofin order to open it by means of a slitting blade and then extract theentrails by means of a suction device and/or carry out cleaning in thisregion by means of scrapers, brushes or the like. In a traditionalprocedure such as is described e.g. in DE 198 29 376 A1, the fish istransported lying on its back in V-blocks of a chain conveyor, butmachines in which it is guided and transported from the outside by meansof conveyor belts are known too. In order to align it in relation to itscentral axis, a guide element is introduced into the abdominal cavity ordigestive tract, which in the case of the prior-art device described iseffected by means of a spike which penetrates into the anus.

[0003] With the known procedures, due to the fact that the fish isguided only relatively loosely in the holding V-blocks of the chainconveyor or between conveyor belts and for example fish deformationcannot be compensated, difficulties arise if the anus or other region ofpenetration is missed by such a spike. As a result of this, the spikepushes the fish sideways and then the point of the spike damages thescales covering the fish in the flank region. However, in particularsubsequent tools such as suction devices, scrapers and above all eventhe slitting knife which here operates in a functional unit with thespike but can also be used separately, which tools are shown e.g. in DE198 29 376 A1, destroy the fish at unwanted locations, thus especiallythe top side of the fish, so that the end product no longer meets thedemanded premium quality requirements. This is a drawback particularlyif, as described there, the aim is to make the so-called “princess cut”,which up to now could be made manually only, by machine (to which cut agutting method refers which ensures a work result which meets thehighest quality requirements and leaves the last 2 to 3 cm of theventral wall in the gill region closed), and if it is wished above allto make noble or high-value fish accessible to machine processing aswell.

[0004] Object

[0005] It is therefore the aim of the invention to provide a remedy withrespect to such difficulties and drawbacks and above all to avoid theabove-mentioned damage.

[0006] In particular, it is the object of the invention to ensure thatthe subsequent tools become operative only in case of functionallyproper penetration of the spike and hence correct positioning of thefish.

[0007] Solution

[0008] This object is achieved in the device set forth above accordingto the invention by the fact that associated with the guide element is amonitoring device which includes a sensor for the guide element/fishposition, an evaluating unit for the comparison of nominal (set) andactual (measured) values, which is connected to the sensor, and anactuating device for the tool, which is connected to this evaluatingunit. With the method of the kind described hereinbefore, according tothe invention the position of the fish relative to the guide element ismonitored, and only on reaching an adjustable nominal position value isa signal for actuating the tool triggered. In other words, according tothe invention both the slitting knife and other, subsequent tools whichare movable relative to the fish come into operation only whenmonitoring with the monitoring device yields an actual value for thefish position which corresponds to the nominal value of the fish whenthe spike has penetrated properly.

[0009] According to a preferred embodiment of the invention, the sensormay be a transmitter/receiver device in particular for electromagneticwaves, wherein monitoring of the fish/guide element position isadvantageously effected optically. In this case a light source can beselected as the sensor, while the receiver can appropriately be arrangedin the guide element itself and connected to the evaluating unit byoptical fibres. In this case, advantageously, modulated light is used toexclude disturbing influences of extraneous light (daylight, lamps,etc.) as far as possible. In this embodiment, the receiver registers themodulated light emanating from the transmitter located outside the fishand preferably above it. If the point of the spike is located in thefish, then the receiver does not register a light signal, and theevaluating unit ascertains matching between actual and nominal values inorder to initiate the actuating signal, whereupon the subsequent toolscan penetrate into the abdominal cavity and work in or on the fish. Ifon the other hand the spike point misses the point of penetration, thatis, the anus, and if it moves outside the abdominal cavity, then thelight emitted by the transmitter is registered by the receiver at thespike point. This circumstance triggers a non-matching signal in theevaluating unit, causing the subsequent tools to remain in their restposition. The fish whose flank remains undamaged can be removed at theend of the conveying path of the transport device and introduced intothe system anew.

[0010] In another advantageous embodiment of the invention, the sensormay be a mechanical feeler for the position of the fish relative to theguide element. In this case, with respect to the method, monitoring ofthe fish/guide element position is effected mechanically, this being bytraining the fish body and monitoring the tracing position relative to anominal value for triggering the signal. Such a feeler is advantageouslymonitored with a proximity switch.

[0011] Appropriately, the feeler may be designed as a double sensinglever with one lever element movable separately from the other on eitherside of the guide element. With respect to the method, tracing iscarried out as double tracing at two tracing points, and the nominalvalue for triggering the signal is determined by comparing tracingpoints. In a structural respect, in this case on either side of thepoint of the guide element is arranged a sensing lever, and the twosensing levers are mounted on a common rotary shaft, their positionbeing monitored or checked by means of the above-mentioned proximityswitch. If the spike, which is arranged centrally between the sensinglevers, is located outside the fish, then the two sensing levers are inthe normal position, and the proximity switch is damped. When the spikehas penetrated into the fish, then the two sensing levers are deflected.Matching between actual and nominal values is registered. Theconsequence is the same as in the embodiment described above for opticalcontrol. If on the other hand the guide element slides over one side ofthe fish, then only the sensing lever between fish and spike isdeflected, whereas the second sensing lever on the side facing away fromthe fish remains in the normal position. This results in registration ofa deviation between actual and nominal values with the consequencesalready described for non-actuation of the tools.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Further advantages and embodiments or options of the inventionare apparent from the description below of the practical examples shownin the schematic drawings. They show:

[0013]FIG. 1A a principle longitudinal-section representation of anoptical monitoring device;

[0014]FIG. 1B a top view of the representation of FIG. 1A;

[0015]FIG. 2A a longitudinal section of a mechanical monitoring device,also as a principle representation, and

[0016]FIG. 2B a top view of the representation of FIG. 2A.

EXAMPLES OF EMBODIMENT

[0017] In FIGS. 1A and B can be seen a first embodiment of a spikeassembly as used for example in a fish gutting machine of the kind shownin DE 198 29 376 A1. A fish 10 held with its ventral side facing upwardsin a conveyor not shown in more detail here is conveyed tail first inthe direction of arrow A. The abdominal cavity 11 and ventral wall 12 ofthe fish are here shown purely schematically. For the purpose ofaligning the fish 10, a guide element designed as a spike 20 is arrangedfor penetration into the abdominal cavity through the anus opening, notdescribed in more detail. This spike 20 comprises in the extent of itswidth a recess in which rotates a slitting blade 21 for slitting openthe abdominal cavity. This slitting blade 21 slits open the fish, whichis kept aligned by the spike 20, in its ventral wall 12 along theventral seam as it advances in the direction of the arrow A, so thatsubsequently tools for extracting the entrails and cleaning theabdominal cavity can become operative.

[0018] In the spike runs, with one end connected to a computer 32 or anevaluating unit 321, an optical fibre 311 of which the other end emergeson the upper side of the spike and ends flush with the latter. This endforms a sensor 31 of which the second functional element is locatedopposite and outside the fish and blade and is a light source 312oriented towards this optical fibre end. Light emitted from the lightsource 312 or other optical signals do not reach the end of the opticalfibre 311 if the spike 20, as shown in the figure, has penetrated intothe abdominal cavity properly and, due to its position in front of theslitting blade 21, is located in the region of the still closed ventralwall 12. The optical fibre 311 connected to the computer 32 on the otherhand receives light if the spike 20 has not correctly penetrated intothe anus, but is located outside the fish on the surface thereof. Inthis case the computer 32 or the evaluating unit 321 registers the lightsignals transmitted through the optical fibre 311. The function of thecomputer lies in converting these received light signals to controlvalues by means of which there can be acted upon stepping motors asactuating members for tools, which are not shown in more detail here andare known from DE 198 29 376 A1, for example. If, as in the first casedescribed, the ventral wall is duly located between light source 312 andsensor 31, then no control signal is generated, and operation of themachine can take its normal course. If, on the other hand, when lightimpinges on the sensor 31 a control signal or signal sequence istriggered in the evaluating unit 321, then this is transmitted to thetools or their actuating members/stepping motors, and the tools remainin their starting position. This concerns in particular also theslitting blade 21 which then remains in its position in the recess ofthe spike 20 in the rest position without intervention in the fish. If,as in the known device, the spike and slitting blade are designed as acommon structural component of the device and hence as a moving unit,then both move back in the direction of arrow B into the common restposition if the spike has not properly and functionally entered theanus. This common pivot movement is performed about an axis lyingoutside the representation, while the spike 20 alone can still pivotabout the axis 210 of the blade 21 in order to be moved out of the fishat the end of cutting it. The movement in the direction of arrow B isperformed once each per fish passing through.

[0019] The further, namely mechanical embodiment shown in FIGS. 2A and Bcan likewise be used in a machine of the kind known from DE 198 29 276A1. The spike 20, which is pivotable about the axis of rotation 210 ofthe slitting blade 21 into the fish, here co-operates with a sensor inthe form of a pair of feelers 315 which is mounted on a pivot shaft 316and pivotable about the latter. On each sensing lever is located amechanical switching element 310 which cooperates with a proximityswitch 322. This proximity switch 322 in turn is connected in switchingrelationship to the computer 32, not shown in more detail here.

[0020] In the position shown in unbroken lines, the spike 20 arrangedcentrally between the sensing levers 315 is located outside the fish,and the two sensing levers are in the normal position, so that theproximity switch is kept damped by the switching element 310. If thespike 20 now functionally enters the anus of the fish, then the twosensing levers are deflected into the position marked 315′. Theproximity switch generates a signal via the computer, and the subsequenttools can be controlled so as to be able to clean the abdominal cavityafter opening of the ventral wall by the slitting blade 21.

[0021] If on the other hand the spike 20 slides over one side of thefish, then only one of the two sensing levers, namely the one located onthe fish side, this being between fish and spike, is deflected. On theother hand, on the side facing away from the fish the sensing lever 315remains in the normal position under the action of a retaining spring317. The proximity switch 322 consequently remains damped; no signal isgenerated.

[0022] Evidently, therefore, by means of the signals generated by theposition of the sensing levers 315 in connection with the mechanicalswitching element 310 in the proximity switch 322, the subsequent toolscan be controlled so as to enter the abdominal cavity only when thespike 20 is properly located in the fish and the slitting blade 21 opensthe ventral wall.

[0023] All in all, therefore, conditions are created by means of theinvention to ensure, in the machine processing of fish, and indeed nobleor high-value fish too, that a product which meets the extremely highquality requirements of nowadays is produced.

1. Device for controlling the commencement of operation of at least onetool in a fish processing machine in which tool and fish are movedrelative to each other along a given conveying path, wherein theposition of the fish (10) in relation to the tool is determined by meansof a guide element (20) which penetrates into the interior (11) of thefish, and after alignment of the fish as a result of penetration of thisguide element the tool (21) begins its engagement on or intervention inthe fish, characterized in that associated with the guide element (20)is a monitoring device (30) which includes a sensor (31) for the guideelement/fish position (20, 10), a computer (32) for comparison ofnominal and actual values, which is connected to the sensor, and anactuator for the tool (21), which is connected to this computer. 2.Device according to claim 1, characterized in that the sensor (31)includes a transmitter/receiver device (311, 312).
 3. Device accordingto claim 2, characterized in that the transmitter is a light source(312) and the receiver forms the end of an optical fibre (311) which isarranged in the guide element (20) and connected to the computer in theform of an evaluating unit (321).
 4. Device according to claim 1,characterized in that the sensor is a mechanical feeler (315) for theposition of the fish (10) relative to the guide element (20).
 5. Deviceaccording to claim 4, characterized in that the feeler is designed as adouble sensing lever (315) with one lever element movable separatelyfrom the other on either side of the guide element (20).
 6. Deviceaccording to any one of claims 1 to 5, characterized in that the guideelement is a spike (20) which penetrates into the fish.
 7. Method forcontrolling the commencement of operation of at least one tool in a fishprocessing machine in which tool and fish are moved relative to eachother along a given conveying path, wherein the position of the fish inrelation to the tool is determined by means of a guide element whichpenetrates into the interior of the fish, and after alignment of thefish as a result of penetration of this guide element the tool beginsits engagement on or intervention in the fish, characterized in that theposition of the fish relative to the guide element is monitored, andonly on reaching an adjustable nominal position value is a signal foractuating the tool triggered.
 8. Method according to claim 7,characterized in that monitoring of the fish/guide element position iseffected optically.
 9. Method according to claim 7, characterized inthat monitoring of the fish/guide element position is effectedmechanically.
 10. Method according to claim 9, characterized in thatmechanical monitoring is effected by scanning the fish's body andmonitoring the sensed position relative to a nominal value fortriggering a signal.
 11. Method according to claim 10, characterized inthat scanning is performed as a double scan at two scanning points, andthe nominal value for triggering a signal is determined by comparison ofscanning points.